The invention relates to a catalyzing fixed bed reactor such as the device disclosed in European Patent Specification 0 396 650. There an exemplified embodiment is described in relation to FIG. 5, i.e. a device which consists of folded layers disposed parallel to one another, each of which comprises a double shell, the walls of which are made from a material which is permeable to the reactants and impermeable to the catalyst material. A catalyst material which is chosen according to the intended use is inserted into the spaces formed by the double walls. The folds of the layers form an angle to the longitudinal axis (i.e. to the main direction of flow) of the device, so that the folds of adjacent layers intersect.
The flow ducts between the packing parts form a static mixer structure. Thanks to this mixer structure an equilibrium of temperature, velocity and concentration which is advantageous for the reaction occurs over the cross section of the column. Furthermore the fact that the pressure drops are relatively small is advantageous.
A disadvantage of the known device is that when filling the double shell of a packing part with catalyst material an unwanted widening of the space is produced because the walls are not sufficiently rigid.